1. Field of the Invention
This invention relates generally to rotary diverter valves and, more specifically, to improvements to bearings and seals for rotary diverter valves.
2. Description of the Prior Art
One of the uses of pneumatic conveyor lines is to transport granular materials from one location to another, oftentimes with selective intermediate diversion of the materials into bins or secondary pneumatic conveying systems. To switch or divert the material from the pneumatic conveyor line into the secondary systems requires a pneumatic switch which will divert the material to the secondary system and some means to seal the connection points on the two systems so that the transported material will not escape into the environment. One of the problems inherent with prior art pneumatic switching devices has been the difficulty in obtaining a good seal as well as obtaining accurate alignment of the conveying tubes of the two systems. If accurate alignment of the conveyor tubes is not maintained, the tubes may become damaged by the fast moving material or leakage of the material may occur. Still other problems inherent with diverting units are that they must withstand large forces because of the high momentum generated by the fast movement of heavy material in the conveyor tubes. The large force makes it difficult to properly seal the pneumatic conveying tubes to the pneumatic switches.
A typical prior art diverter valve is shown in the Baresch U.S. Pat. No. 2,690,931. Baresch uses a pneumatic apparatus for conveying powdered granular material to either of two discharge conducts. Baresch shows no seals on the discharge conduit to prevent flow past the junction.
Still another type of device is shown in the Yates Great Britain patent specification No. 229,844. Yates shows the ends of several pipes around a common circle whose center is on the axis of a single pipe that swivels thereabout.
Still another type of changeover means for pneumatic lines is shown in the Sebestyn U.S. Pat. No. 2,825,604. Sebestyn shows a changeover means having expandable rings to seal the gap between the tube pipes.
A further prior art apparatus for distributing material is shown in the Great Britain specification No. 1,382,347 which shows a distributer for material conveyed by gravity or pneumatically. The Great Britain patent shows a platform with selected pipe outlets and a platform having a pipe which is alignable therewith. The patent shows at least one annular inflatable joint to provide a seal between the pipe and the selected outlet.
The concept of other types of inflatable seals is shown in the French Pat. No. 7,413,252 which shows an inflatable seal for use around doors, etc.
The German prior art patent No. 2,051,117 shows a system in which one or more sealing pistons are forced by the internal pressure into sealing against the outlet ports not in use.
The present invention is an improvement to the above-identified prior art devices. More specifically, the present invention provides a positionable unit that includes a band bearing and a pair of inflatable seals that permit sealing the rotatable conveyor tube to the inlet and outlet.